Khor Chu Yee
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Preferred name
Khor Chu Yee
Official Name
Khor, Chu Yee
Alternative Name
Yee, Khor Chu
Khor, Chu Yee
Khor, C. Y.
Yee, K. C
Main Affiliation
Scopus Author ID
57193315174
Researcher ID
B-1541-2014

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  • Publication
    Effect of Ni on the suppression of sn whisker formation in Sn-0.7Cu solder joint
    ( 2021)
    Aimi Noorliyana Hashim
    ;
    Mohd Arif Anuar Mohd Salleh
    ;
    Andrei Victor Sandu
    ;
    Muhammad Mahyiddin Ramli
    ;
    Khor Chu Yee
    ;
    Noor Zaimah Mohd Mokhtar
    ;
    Jitrin Chaiprapa
    The evolution of internal compressive stress from the intermetallic compound (IMC) Cu6Sn5 growth is commonly acknowledged as the key inducement initiating the nucleation and growth of tin (Sn) whisker. This study investigates the effect of Sn-0.7Cu-0.05Ni on the nucleation and growth of Sn whisker under continuous mechanical stress induced. The Sn-0.7Cu-0.05Ni solder joint has a noticeable effect of suppression by diminishing the susceptibility of nucleation and growth of Sn whisker. By using a synchrotron micro X-ray fluorescence (µ-XRF) spectroscopy, it was found that a small amount of Ni alters the microstructure of Cu6Sn5 to form a (Cu,Ni)6Sn5 intermetallic layer. The morphology structure of the (Cu,Ni)6Sn5 interfacial intermetallic layer and Sn whisker growth were investigated by scanning electron microscope (SEM) in secondary and backscattered electron imaging mode, which showed that there is a strong correlation between the formation of Sn whisker and the composition of solder alloy. The thickness of the (Cu,Ni)6Sn5 IMC interfacial layer was relatively thinner and more refined, with a continuous fine scallop-shaped IMC interfacial layer, and consequently enhanced a greater incubation period for the nucleation and growth of the Sn whisker. These verification outcomes proposes a scientifically foundation to mitigate Sn whisker growth in lead-free solder joint.
  • Publication
    Biomass fuel characteristics of Malaysian Khaya Senegalensis wood-derived energy pellets: effects of densification at varied processing temperatures
    ( 2024)
    Ras Izzati Ismail
    ;
    Khor Chu Yee
    ;
    Alina Rahayu Mohamed
    This study addresses the effects of densification at varied pelletization temperatures on the novel Malaysian Khaya senegalensis wood-derived pellets biomass fuel characteristics. The lack of comprehensive understanding regarding the biomass fuel characteristics of this species prompted the research. By addressing this knowledge gap, this study explores the impact of temperature variations on key fuel properties, contributing to the optimization of sustainable biomass fuel production in manufacturing and materials processing. Khaya senegalensis wood, grown and harvested in Malaysia, was pelletized at different temperatures to analyze the calorific value, volatile matter content, ash content, fixed carbon, bulk density, and moisture contents of the pellets. The experimental data revealed a significant relationship between temperature and these fuel properties. Pelletizing at 75 °C produced the highest calorific value of 19.47 MJ/kg and the maximum fixed carbon content of 10.04%. A low ash level of 4.26% was achieved via pelletizing at 75 °C. According to the results, 75 °C produced the best thermophysical properties. These findings provide valuable understanding of how pelletization temperature influences fuel pellet thermophysical properties, a critical aspect in optimizing fuel pellet production, storage, advancing renewable energy resource utilization, and, finally, promoting a cleaner and more sustainable energy future.
  • Publication
    Chip morphology and surface integrity in turning AZ31 magnesium alloy under dry machining and submerged convective cooling
    ( 2023)
    Muhammad Syamil Zakaria
    ;
    Mazli Mustapha
    ;
    Azwan Iskandar bin Azmi
    ;
    Khor Chu Yee
    Magnesium alloys have broad applications, including medical implants and the aerospace sector owing to their great density and high strength-to-weight ratio. Dry cutting is a frequent technique for machining this material. However, it always leads to an excessive rise in temperature due to the absence of cooling at the cutting zone, which affects the machined surface integrity and chip morphology. In this study, chip morphology and surface integrity of the AZ31 magnesium alloy were investigated in the turning process using an internal cooling method called submerged convective cooling (SCC) to overcome the absence of cooling in dry cutting. This method can exploit the advantage of the high specific heat capacity of water as a cooling fluid without any reaction between water and magnesium to create a cooling element in the cutting zone. The chip morphologies and surface integrity were analyzed experimentally with varying cutting speeds under SCC and dry cutting. The experimental results revealed that SCC and dry cutting produced saw-tooth or serrated chip formation. The chips produced in dry cutting were continuous, while SCC was short and discontinuous as a result of a severe crack on the back surface of the chip. It was discovered that the grain refinement layer on the machined samples was thinner under SCC turning. SCC machining increased the microhardness of the AZ31 magnesium alloy by 60.5% from 55 HV to 88.3 HV, while dry turning exhibited a 49% increase in microhardness. The result revealed that surface roughness improved by 10.8%, 9.4% and 4.7% for cutting speeds (V) of 120, 180, and 240 m/min, respectively, under the SCC internal cooling. Based on the result obtained, SCC cutting outperformed dry cutting in terms of chip breakability, grain refinement, microhardness, and surface roughness.
  • Publication
    Antioxidant capacity and total phenolic content of fresh, oven-dried and stir-fried tamarind leaves
    ( 2017)
    Lee Yit Leng
    ;
    Mohd Nadzrin Mohammad Radzi
    ;
    Abd Razak Shaari
    ;
    Norawanis Abdul Razak
    ;
    Khor Chu Yee
    The aim of this study was to compare the antioxidant capacity and total phenolic content as well as the chemical groups of fresh, oven-dried and stir-fried tamarind (Tamarindus indica L.) leaves. Methanol was used for extraction of fresh, oven-dried and stir-fried tamarind leaves. The stir-fried leaves were prepared using medium heat for 10 minutes prior to extraction and chemical analysis while dried leaves were obtained by oven drying at 60°C for 3 hours. The stir-fried leaves had significantly highest total phenolic content (TPC) (139.87 mg/g) and percentage DPPH radical-scavenging inhibition (69.92%) while the fresh leaves had the lowest TPC (39.31 mg/g) and antioxidant capacity (16.46%). The FTIR spectral data suggest that the heat treatment increased the amine groups as well as the antioxidant capacity of the tamarind leaves. To increase the antioxidant capacity, the tamarind leaves should be prepared in a stir-frying process.
  • Publication
    Optimization of fuel pellet parameter from oil palm fronds by using Response Surface Methodology (RSM)
    ( 2023-06)
    Ras Izzati Ismail
    ;
    Khor Chu Yee
    ;
    Alina Rahayu Mohamed
    ;
    Nadiah Farzana Jamaludin
    ;
    Adli Azimi Abdul Rahman
    ;
    Mohd Riduan Jamalludin
    The oil palm tree, which had been producing a plentiful supply of oil palm fronds, had simply been left to rot on the ground. As biomass is a loose substance, pelletization was undertaken so that it could be transported and stored with ease. High-quality pellet production was studied to maximize oil palm frond use. Therefore, the primary goal of this study was to determine the impact of particle size and moisture content on fuel pellet quality. The response surface approach was utilized in this study to optimize the oil palm fronds pellet particle size and the moisture content on the durability, unit density, and calorific value. The particle sizes analyzed were 0.15 mm, 0.500 mm, and 1.00 mm, while the moisture content was 5%, 10.50%, and 16%. The pellets were manufactured using a hydraulic single pellet press, and their calorific value, unit density, and durability were evaluated using a bomb calorimeter, a density formula, and a sieve shaker, respectively. The optimization yielded the maximum desirability (0.5026) for particles with a 16% moisture content and a 0.500 mm particle size. The condition is ideal when the value of desirability is closest to 1.00. It may be concluded that the particle size and moisture content of oil palm fronds affect the durability, unit density, and calorific value of oil palm fronds pellet.
  • Publication
    Cracking the code: process parameter effects on Khaya senegalensis energy pellet moisture content
    ( 2023-12)
    Ras Izzati Ismail
    ;
    Khor Chu Yee
    ;
    Alina Rahayu Mohamed
    The production of energy pellets from biomass sources holds immense potential for sustainable renewable energy generation. This study investigates the influence of key process parameters on the moisture content of energy pellets derived from Khaya senegalensis, a promising biomass feedstock in Malaysia. With a focus on unlocking the relationship between process variables and pellet moisture, a systematic experimental approach was adopted. The objective of this study is to investigate the effects of raw material moisture, feedstock particle size, compression pressure, and pelletization temperature on the manufactured biomass energy pellet's moisture content. By employing a comprehensive design of experiments and statistical analysis, the nuanced effects of these parameters are revealed on the moisture content of Khaya senegalensis energy pellets. The results illuminate the complex interplay between these process variables and the final moisture characteristics of the pellets. Understanding how these parameters impact moisture content is crucial for optimizing pellet quality, combustion efficiency, and storage stability. The study found a quadratic relationship between particle size, compression pressure, and pelletization temperature, indicating that larger particle sizes correlate with higher moisture content. Excessive pressure led to elevated levels while increasing temperature showed a decreasing trend. This research contributes valuable insights that advance the knowledge frontier of biomass pelletization, paving the way for enhanced utilization of Khaya senegalensis as a renewable energy resource.
  • Publication
    Effect of Ni on the suppression of Sn whisker formation in Sn-0.7Cu solder joint
    ( 2021)
    Aimi Noorliyana Hashim
    ;
    Mohd Arif Anuar Mohd Salleh
    ;
    Andrei Victor Sandu
    ;
    Muhammad Mahyiddin Ramli
    ;
    Khor Chu Yee
    ;
    Noor Zaimah Mohd Mokhtar
    ;
    Jitrin Chaiprapa
    The evolution of internal compressive stress from the intermetallic compound (IMC) Cu6Sn5 growth is commonly acknowledged as the key inducement initiating the nucleation and growth of tin (Sn) whisker. This study investigates the effect of Sn-0.7Cu-0.05Ni on the nucleation and growth of Sn whisker under continuous mechanical stress induced. The Sn-0.7Cu-0.05Ni solder joint has a noticeable effect of suppression by diminishing the susceptibility of nucleation and growth of Sn whisker. By using a synchrotron micro X-ray fluorescence (µ-XRF) spectroscopy, it was found that a small amount of Ni alters the microstructure of Cu6Sn5 to form a (Cu,Ni)6Sn5 intermetallic layer. The morphology structure of the (Cu,Ni)6Sn5 interfacial intermetallic layer and Sn whisker growth were investigated by scanning electron microscope (SEM) in secondary and backscattered electron imaging mode, which showed that there is a strong correlation between the formation of Sn whisker and the composition of solder alloy. The thickness of the (Cu,Ni)6Sn5 IMC interfacial layer was relatively thinner and more refined, with a continuous fine scallop-shaped IMC interfacial layer, and consequently enhanced a greater incubation period for the nucleation and growth of the Sn whisker. These verification outcomes proposes a scientifically foundation to mitigate Sn whisker growth in lead-free solder joint.
  • Publication
    Computational Fluid Dynamics Analysis of Varied Cross-Sectional Areas in Sleep Apnea Individuals across Diverse Situations
    ( 2024-01-01)
    Faizal W.M.
    ;
    Khor Chu Yee
    ;
    Mohamad Suhaimi Shahrin
    ;
    Mohd. Hazwan Mohd. Hanid
    ;
    Masniezam Ahmad
    ;
    Misbah M.N.
    ;
    Haidiezul A.H.M.
    Obstructive sleep apnea (OSA) is a common medical condition that impacts a significant portion of the population. To better understand this condition, research has been conducted on inhaling and exhaling breathing airflow parameters in patients with obstructive sleep apnea. A steady-state Reynolds-averaged Navier–Stokes (RANS) approach and an SST turbulence model have been utilized to simulate the upper airway airflow. A 3D airway model has been created using advanced software such as the Materialize Interactive Medical Image Control System (MIMICS) and ANSYS. The aim of the research was to fill this gap by conducting a detailed computational fluid dynamics (CFD) analysis to investigate the influence of cross-sectional areas on airflow characteristics during inhale and exhale breathing in OSA patients. The lack of detailed understanding of how the cross-sectional area of the airways affects OSA patients and the airflow dynamics in the upper airway is the primary problem addressed by this research. The simulations revealed that the cross-sectional area of the airway has a notable impact on velocity, Reynolds number, and turbulent kinetic energy (TKE). TKE, which measures turbulence flow in different breathing scenarios among patients, could potentially be utilized to assess the severity of obstructive sleep apnea (OSA). This research found a vital correlation between maximum pharyngeal turbulent kinetic energy (TKE) and cross-sectional areas in OSA patients, with a variance of 29.47%. Reduced cross-sectional area may result in a significant TKE rise of roughly 10.28% during inspiration and 10.18% during expiration.